Measurement of eye rotations in three dimensions and the retinal stimulus projection using scanning laser ophthalmoscopy

A transformation algorithm is introduced to specify eye rotations in three dimensions from two-dimensional translations of ocular fundus landmarks dynamically monitored by means of the novel Scanning Laser Ophthalmoscope (SLO). The rotation parameters are expressed as Y-X-Z Euler angles and in terms of the rotation axis and one rotation angle. Additionally, the angular distance of the retinal stimulus projection can be evaluated relative to the fovea. By simultaneously operating as eye movement measurement device, fundus camera, and visual target projector, the SLO opens a variety of new applications for the combined analysis of eye movements and the underlying 'retinal events' in vision and oculomotor research.